1. Field of the Invention
The present invention relates to a paper regulating mechanism and a paper cassette in a paper feed cassette mounted in a copying machine, for example, for accommodating sheets of copying paper.
2. Related Art of the Invention
In the prior art, for example, a copying machine is equipped with several paper feed cassettes, as shown in FIG. 2, for accommodating paper sheets having a plurality of sizes simultaneously. These paper feed cassettes are coarsely divided into the type, in which the size of paper to be accommodated is fixed, and the type in which the size of paper to be accommodated can be freely set.
A copying machine 101, as shown in FIG. 2, is equipped with the paper feed cassette of the latter type, the construction of which will be described in the following with reference to FIGS. 2 and 3.
Here, FIG. 2 is a partially cut-away section showing a side view of the body of copying machine 101, and FIG. 3 is a schematic perspective view of the paper feed cassette shown in FIG. 2.
In FIG. 2, a first paper feed cassette 105 is one capable of accommodating the paper sheets 104 of any size if the size falls within the size range of A3 to B5. This first paper feed cassette 105 is slidably disposed in the central portion of the copying machine 101. A front panel 103 is attached to the front face of the first paper feed cassette 105 and equipped with a knob portion 103a which is used to pull the first paper feed cassette 105 toward the operator standing in front. The portion in the first paper feed cassette 105 for accommodating the paper sheets 104 is arranged, as will be described hereinafter, with a bottom plate 111 for placing the paper sheets 104 and a pair of paper regulating plates 112 (for regulating the side portions) made horizontally movable for preventing the paper sheets 104 from slipping in a direction perpendicular to the paper feeding direction.
A second paper feed cassette 106 and a third paper feed cassette 107 are given constructions similar to that of the first paper feed cassette 105 and are slidably disposed below the first paper feed cassette 105.
Next, as shown in FIG. 3, the bottom plate 111 is a plate for setting the paper sheets 104 and is formed in predetermined portions with a pair of openings 114. The paper regulating plate 112 has its side face formed into a generally letter "L" shape, of which a horizontal portion is extended to form a rack portion 112a at its one side whereas a vertical portion is formed into a paper regulating portion 112b arranged to extend through the opening 114. Moreover, the paired paper regulating plates 112 are constructed to face the individual paper regulating portions 112b and the portions of the individual rack portions 112a.
Between the rack portions 112a having their portions facing each other, there is rotatably arranged a pinion portion 113. These components are constructed to mesh each other completely without any idle motion thereby to move the paired paper regulating plates 112 the same distance in the direction perpendicular to the paper feeding direction.
In the individual paper feed cassettes equipped with the paper regulating mechanisms thus constructed, the following operations are usually performed in case: the first paper feed cassette 105 is charged with the paper sheets of A4 size; the second paper feed cassette 106 is charged with the paper sheets of B4 size; and the third paper feed cassette 107 is charged with the paper sheets of A3 size, and in case the operator is about to change the sizes of paper sheets already accommodated.
Specifically, the operator pulls the second paper feed cassette 106 to his side (as shown in FIG. 2) by inserting his hand into the knob portion 103a so that the paper sheets 104 of B4 size accommodated in the second paper feed cassette 106 may be renewed by those of B5 size. The paper sheets 104 of B4 size accommodated in advance in the second paper feed cassette 106 pulled out are removed, and a predetermined number of paper sheets 104 of B5 size are placed on the bottom plate 111 in a generally central portion of the paired paper regulating plates 112, as shown in FIG. 3. In order to narrow the gap between the paired paper regulating plates 112 to the width of the paper sheets, moreover, the individual paper regulating portions 112b are manually moved toward each other by a predetermined force and are stopped at positions corresponding to the width of the paper sheets of B5 size. As a result, the positions of the paper sheets 104 of B4 size can be properly regulated.
Thus, the paper regulating mechanism must accomplish the different functions of preventing the paper sheets 104 from slipping during a copying operation while permitting the paper regulating plates 112 to be moved manually when replacing the paper sheets 104. The prior art of the paper feeding mechanism is disclosed in Japanese Patent Laid-Open No. 21850/1979 or Japanese Utility Model Laid-Open No. 62739/1982, for example.
Even if, however, the prior art paper regulating plates 112 are made to prevent the paper sheets 104 from slipping, they still must be able to be moved by a predetermined manual force. As a result, paper slip prevention is limited in prior art copying machines 101 since if excessive forces are used when loading or unloading the paper cassette, for example, this force may cause the regulating plates 112 to move, thereby permitting the paper sheets 104 to move from their normal output position such that normal copying operations are made more difficult, if not impossible.
As a method for solving this problem, there has been proposed and utilized a structure in which the paper regulating plates 112 are equipped with a lock mechanism for fixing the plates 112 more reliably to prevent any movement of them. As a result, if the lock mechanism is released at the time of exchanging the paper sheets 104, the paper regulating plates 112 can be manually moved as in the prior art. During the copying operation, moreover, the paper regulating plates 112 can be locked to prevent the slip of the paper sheets 104.
This construction, however, stresses preventing slipping of the paper sheets 104 to the detriment of being able to manually move the paper regulating plates 112 easily when exchanging the paper sheets to the extent that in the prior art, it was sufficient if the plates 112 could be moved at all.
Thus, in these prior art paper cassettes, although the paper sheets 104 could be reliably fixed to prevent the paper sheets from slipping (except for the case when the paper sheets 104 are to be exchanged), there still existed the need for the ability to move the paper regulating plates 112 smoothly and without great force when exchanging the paper sheets 104.
On the other hand, in the paper cassette of the prior art disclosed in Japanese Utility Model Publication No. 120732/1984, for example, a pin for mounting a paper stopper is inserted and retained in a mounting hole formed in the bottom face of the paper cassette, and the mounting hole is formed in a plurality of positions for the paper sheets of individual sizes so that the mounting position of the paper stopper is changed in conformity to the size of the paper sheets to be used (as corresponds to the paper regulating plates for the rear portions).
These prior art cassettes, however, have the problem that it is difficult to move the paper stopper when changing the paper size. Specifically, it is cumbersome to insert and remove the mounting pin of the paper stopper into and out of the mounting hole, respectively. Moreover, in order to securely fix the paper stopper, the fit between the mounting pin and the mounting hole has to be considerably tight. This arrangement, however, makes the mounting and demounting the paper stopper even more difficult. Furthermore, the paper stopper may be lost or damaged when it is removed. Another drawback of this arrangement is that the number of paper sizes which can be used is limited to the predetermined mounting hole positions where the paper stopper can be inserted.
Considering those problems of the paper regulating mechanism and the paper stopper of the prior art, the present invention has an object to provide a paper regulating mechanism and a stopper, which can move the paper regulating plate and the stopper smoothly by a weak force to make the paper exchanging operations easier than those of the prior art and to prevent the slip of the paper sheets reliably.